The present invention relates to a quick coupler for the coupling of a tool to a boom having a quick coupling part on the boom side and a quick coupling part on the tool side having a circuit coupling, including a hydraulic coupling, having plate-like supports for the power coupling parts for the automatic coupling of a power connection at the tool side to a power connection at the boom side, with male or female connector pieces being integrated in the plate-like supports, on the one hand, as power connections and with at least one guide bolt or at least one guide bore being integrated spaced apart therefrom in the plate-like supports, which ensure an exactly fitting lying of the plate-like supports on top of one another in the coupled state such that the plate-like supports are arranged largely parallel to one another while forming a small gap.
Quick couplers of the pivot type are widespread in hydraulic excavators, since they permit a simple and fast change of different tools such as hydraulic grabs, digging-stripping shovels, gripping tongs and the like. Initially, only one of the two latching axles has to be positioned and brought into engagement for the coupling. It can advantageously be a cross bolt which is hung into a hook-like eyelet on the oppositely disposed coupling part. The coupling part at the boom side can then be pivoted relative to the tool around the latching axle already brought into engagement, in order hereby to find the latching position in which the second latching axle can be latched. The latter is, as a rule, formed by a pair of latching bolts which can move apart and into corresponding latching bores on the oppositely disposed quick coupling part.
Such a quick coupling of the pivot type is known from WO 91/01414 in which an automatic hydraulic coupling is provided which automatically couples a power circuit on the boom side to a power circuit on the tool side on the pivoting together of the two quick coupling parts. Power coupling parts are admittedly provided, of which one is fastened to the quick coupling on the boom side and the other is fastened to the quick coupling part on the tool side, and indeed such that the two power coupling parts are moved toward one another and are brought into engagement when the two quick coupling parts are pivoted together around the first, already latched latching axle. One of the two power coupling parts is movably supported on the corresponding quick coupling part to compensate the circular movement of the quick coupling parts when pivoted together.
A generic coupling is known from DE 101 59 417 C2. To permit a leak-free and defect-free coupling of the power circuits on the boom side and on the tool side, in this prior-known quick coupling, a linear guide for the power coupling parts is known which forces the power coupling parts against the circular pivot movement into a relative movement with respect to one another along a straight line. To permit the compensation of the pivot movement, at least one of the two power coupling parts is movably supported on the corresponding quick coupling part relative thereto, and indeed pivotable around an axle parallel to the first latching axle of the quick coupling parts and perpendicular thereto. Provision is made in this process for the movably supported power coupling part to compensate the pivot movement by a linear guide on the moving together of the quick coupling parts and to move precisely such that an exactly linear movement takes place between the two power coupling parts. At least one guide bolt or one guide bore serve for this purpose, which engage into one another on coupling and ensure an exactly fitting lying of plate-like supports on top of one another in the coupled state such that the plate-like supports are arranged largely parallel to one another while forming a small gap in the coupled state.